Webbing retractor

Abstract

A webbing retractor includes a spool around which a webbing is wound in such a manner as to be capable of being pulled out; an energy absorbing member which is deformed by the spool when a rotating force acting in a pulling-out direction of the webbing is applied to the spool at the time of a sudden deceleration of a vehicle, so as to prevent an increase in a tensile force of the webbing; a pretensioner which is connected to the spool when a deceleration of a predetermined value or more is applied, so as to rotate the spool in a taking-up direction of the webbing; and a canceling portion disposed between the spool and the pretensioner so as to cancel the stopping of rotation in a paying-out direction of the webbing by the pretensioner after operation of the pretensioner. Accordingly, after the operation of the pretensioner, the rotation of the spool in the pulling-out direction of the webbing is not restricted, and the energy absorption by the energy absorbing member is not restricted.

What is claimed is: 
     
       1. A webbing retractor comprising: a spool around which a webbing is wound in such a manner as to be capable of being pulled out;   an energy absorbing member which is actuated by said spool when a rotating force acting in a pulling-out direction of the webbing is applied to said spool at the time of a sudden deceleration of a vehicle, so as to prevent an increase in a tensile force of the webbing;   a pretensioner which is connected to said spool when a deceleration of a predetermined value or more is applied, so as to rotate said spool in a taking-up direction of the webbing; and   a canceling portion including a deformable portion disposed between said spool and said pretensioner for deformably canceling the stopping of rotation in a paying-out direction of the webbing by said pretensioner after operation of said pretensioner.   
     
     
       2. A webbing retractor according to claim 1, wherein said canceling portion cancels the stopping of rotation in the paying-out direction of the webbing by said pretensioner in a state in which the rotating force acting in the pulling-out direction of the webbing is applied to said spool after the operation of said pretensioner. 
     
     
       3. A webbing retractor according to claim 1, wherein said canceling portion cancels the stopping of rotation in the paying-out direction of the webbing by said pretensioner in a state in which said spool is rotated in the pulling-out direction of the webbing after the operation of said pretensioner. 
     
     
       4. A webbing retractor according to claim 1, wherein said canceling portion cancels the stopping of rotation in the paying-out direction of the webbing by said pretensioner if a deforming force applied to said energy absorbing member by the rotating force in the pulling-out direction of the webbing exceeds a predetermined value after the operation of said pretensioner. 
     
     
       5. A webbing retractor according to claim 1, wherein said canceling portion is a breakable portion which is connected to said spool and said pretensioner, and separates a side thereof connected to said spool and a side thereof connected to said pretensioner as said canceling portion is broken. 
     
     
       6. A webbing retractor according to claim 1, wherein said energy absorbing member is a torsion bar having one end connected to said spool and another end connected to an inertial lock mechanism which responds to an acceleration. 
     
     
       7. A webbing retractor according to claim 6, wherein said torsion bar is disposed coaxially with said spool. 
     
     
       8. A webbing retractor according to claim 6, wherein said canceling portion connected to said pretensioner extends integrally from one end of said torsion bar so as to serve as a portion subject to torsional breakage. 
     
     
       9. A webbing retractor according to claim 6, wherein said torsion bar is connected to said spool and said inertial lock mechanism through engagement between a prismatic bar and a prismatic hole. 
     
     
       10. A webbing retractor according to claim 6, wherein said canceling portion extends to one end of said energy absorbing member. 
     
     
       11. A webbing retractor according to claim 7, wherein an inserting portion which is connected to said pretensioner extends from said energy absorbing member, and said canceling portion is disposed between said inserting portion and said energy absorbing member. 
     
     
       12. A webbing retractor according to claim 11, wherein said inserting portion has a prismatic shape. 
     
     
       13. A webbing retractor according to claim 1, wherein said energy absorbing member is inserted into said spool coaxially therewith, a prismatic portion at one end of said energy absorbing member is engaged with an inertial lock mechanism which responds to an acceleration, an inserting portion at another end of said energy absorbing member is engaged with said pretensioner, an engaging portion adjacent to said inserting portion is engaged with said spool, a portion between said inserting portion and said engaging portion serves as a breakable portion, and a portion between said engaging portion and said prismatic portion at said one end serves as an energy absorbing portion. 
     
     
       14. A webbing retractor comprising: a spool around which a webbing is wound in such a manner as to be capable of being pulled out;   an energy absorbing member which is deformed by said spool when a rotating force acting in a pulling-out direction of the webbing is applied to said spool at the time of a sudden deceleration of a vehicle, so as to prevent an increase in a tensile force of the webbing;   a pretensioner which is connected to said spool when a deceleration of a predetermined value or more is applied, so as to rotate said spool in a taking-up direction of the webbing; and   a canceling portion including a yieldable portion of said energy absorbing member disposed between said spool and said pretensioner so as to cancel the stopping of rotation in a paying-out direction of the webbing by said pretensioner if a deforming force applied to said energy absorbing member by the rotating force in the pulling-out direction of the webbing exceeds a predetermined value after operation of said pretensioner.   
     
     
       15. A webbing retractor according to claim 14, wherein said canceling portion is a breakable portion which is connected to said spool and said pretensioner, and separates a side thereof connected to said spool and a side thereof connected to said pretensioner as said canceling portion is broken. 
     
     
       16. A webbing retractor according to claim 14, wherein said energy absorbing member is a torsion bar having one end connected to said spool and another end connected to an inertial lock mechanism which responds to an acceleration, and said canceling portion connected to said pretensioner extends integrally from one end of said torsion bar so as to serve as a portion subject to torsional breakage. 
     
     
       17. A webbing retractor according to claim 14, wherein said energy absorbing member is disposed coaxially with said spool. 
     
     
       18. A webbing retractor according to claim 17, wherein an inserting portion which is connected to said pretensioner extends from said energy absorbing member, and said canceling portion is disposed between said inserting portion and said energy absorbing member. 
     
     
       19. A webbing retractor according to claim 14, wherein said energy absorbing member is inserted into said spool coaxially therewith, a prismatic portion at one end of said energy absorbing member is engaged with an inertial lock mechanism which responds to an acceleration, an inserting portion at another end of said energy absorbing member is engaged with said pretensioner, an engaging portion adjacent to said inserting portion is engaged with said spool, a portion between said inserting portion and said engaging portion serves as a breakable portion, and a portion between said engaging portion and said prismatic portion at said one end serves as an energy absorbing portion. 
     
     
       20. A webbing retractor comprising: a spool around which a webbing is wound in such a manner as to be capable of being pulled out;   a pretensioner which is connected to said spool when a deceleration of a predetermined value or more is applied, so as to rotate said spool in a taking-up direction of the webbing;   an energy absorbing member which is inserted into said spool coaxially therewith, wherein a prismatic portion at one end of said energy absorbing member is engaged with an inertial lock mechanism which responds to an acceleration, an inserting portion at another end of said energy absorbing member is engaged with said pretensioner, an engaging portion adjacent to said inserting portion is engaged with said spool, a portion between said inserting portion and said engaging portion serves as a breakable portion, and a portion between said engaging portion and said prismatic portion at said one end serves as an energy absorbing portion which is deformed by said spool when a rotating force acting in a pulling-out direction of the webbing is applied to said spool at the time of a sudden deceleration of a vehicle, so as to prevent an increase in a tensile force of the webbing; and   a canceling portion including said breakable portion disposed between said spool and said pretensioner so as to cancel the stopping of rotation in a paying-out direction of the webbing by said pretensioner after operation of said pretensioner.